Question

A wheel rotates making $20$ revolutions per second. If the radius of the wheel is $35cm$, what linear distance does a point of its rim traverse in three minutes? (take $\pi =22/7$)

• A. $7.92km$
• B. $7.70km$
• C. $7.80km$
• D. $7.85km$

Answer 1

Answer: (A)

Radius of the wheel $=35cm$
$\therefore$ Circumference of the wheel $=2\pi \times 35cm=220cm$.
Hence, the linear distance travelled by a point of the rim in one revolution $=220cm$.
Number of revolutions made by the wheel in $3$ minutes
$=20\times 3\times 60=3600$.
$\therefore$ The linear distance travelled by a point of the rim in $3$ minutes $=220\times 3600=792000cm=7.92km$.